1. Field of the Invention
The present invention relates to an image reading apparatus which is used for reading, for example, a form sheet in which the user fills a form printed in a predetermined format, such as a betting card or a mark sense card.
2. Description of the Related Art
A reading apparatus and an image processing apparatus are in widespread use. In such an apparatus, betting cards issued in various stadiums for horse racing, bicycle racing, boat racing, and the like, or those for lottery such as LOTO in which betting is performed by selecting one of printed numbers are read by a device, the written or selected numerical value or symbol is determined, and the reading result as a betting card record is notified and returned to the user.
In a betting card, usually, in order to improve the convenience of the user and simplify a process of specifying a written or selected numerical value or a symbol position in a reading apparatus, printing serving as a guide for writing or selection is performed in portions where a numerical value or symbol is to be written or selected. When numerical values or symbols written or selected by writing instruments of various colors or kinds are to be extracted from form sheets, such a guide printed portion constitutes unwanted information. Therefore, an image processing apparatus or drop processing apparatus which comprises means for dropping out a guide printed portion from a read image, and reading only a written or selected numerical value or symbol has been proposed.
For example, JP-A-2006-339875 discloses in FIG. 1 an image processing apparatus which performs a dropout process by extracting image data existing in a predetermined region of image information, and substituting a specific color with predetermined pixel data on the basis of extracted pixel data. A perceptible color space is divided into color space regions, typical colors of the color space regions are displayed as a color palette on a displaying device of the image processing apparatus, and the user selects a color to be dropped out, thereby designating the specific color. The image in which the specific color is substituted is displayed on the displaying device so that the user can check the process result.
JP-A-2003-216894 discloses in FIG. 1 a dropout process in which a histogram producing portion 14 performs SVH conversion on RGB of a subregion image to produce a histogram with respect to S, V, and H, a color information setting portion 15 obtains information of a color to be dropped out from the histogram, the value of the information is set in a color table to be stored, and, in the case where a pixel of a color image of a form sheet 3 corresponds to the color information of the color table, a binarizing portion 16 binarizes the pixel as a background pixel.